I've had two pairs of these and both lasted around 4 years of heavy use. Was a bit disappointed with how they lasted, but they were extremely comfortable and fit very well.

After those, I switched to a pair of Meindl's (looked very sturdy, thick leather all round, easy to replace the outsoles when needed). They were much less comfortable than the Lowa, and the inner lining around the heel ripped from both shoes in just a few months.